Energy management in buildings requires that indoor air be heated in cold weather to overcome losses due to heat conduction throughout the structure and convection due to leakage around windows, doors and other ports. Even with well insulated and tighter buildings, indoor air replacement is necessary to clear the air of pollutants formed from cooking, smoking, etc. Heating requirements can be reduced where outdoor air being brought in is heated by exchange with the indoor air being replaced. However, current heating methods are indirect; they involve burning a fuel at some central location, transferring the energy from that fuel to a fluid and a heat exchanger, and then transferring the energy from that fluid or secondary fluid through another heat exchanger to the air to be warmed. Alternative methods of heating using electricity are even less efficient.
Commonly assigned U.S. Pat. No. 4,614,176 describes an apparatus for heating air wherein hydrogen combustion is dispersed in direct proximity to a metal hydride fuel source in order that the combustion heat effects the release of the hydrogen from the metal hydride. The combustion area contains a catalyst and a semipermeable membrane separates the hydride fuel storage means and the combustion area. The temperature of the metal hydride is raised to effect initial release of hydrogen which passes through the semipermeable membrane, mixes with air and is combusted at the catalyst. The heat of combustion, in direct proximity to the metal hydride, perpetuates the hydrogen release. Although this system provides advantages, the metal hydrides can be heavy, expensive and require periodic replacement and regeneration.
Accordingly, there is a search in this art for apparatuses that do not rely upon metal hydride systems.